The present invention relates generally to overhead cranes, and more specifically, to a reel hoist interlock system for use with an overhead crane.
Overhead cranes, such as bridge cranes and gantry cranes, are currently used in a large number of industrial applications to move materials during manufacturing processes. In general, overhead cranes are used to lift objects using hoists which move horizontally on a rail, or pair of rails. Overhead cranes are particularly suited to lifting very heavy objects where the crane straddles the object to be lifted and moved.
Currently, overhead cranes are used to move large objects, such as large rolls of paper, from one location to another during a manufacturing process. As shown in FIG. 1, a typical overhead crane 100 includes a gantry 102, or supporting beam, which travels on a pair of rails 104. The overhead crane 100 also includes a pair of hoists 106, such as reel hoists, that are disposed on the gantry 102. Each hoist 106 is connected to a hook 108 configured to engage the object 110 to be moved. Typically, the overhead crane 100 is operated by a remote 112 that controls the movement of the gantry 102 along the rails 104 as well as the operation of the hoists 106 to raise and lower the hooks 108. In most cases, the remote 112 is physically connected to the overhead crane 100 and the operator of the remote 112 is located near the object 110 to be moved.
In many cases, due to the size of the object 110 to be moved, the operator of the overhead crane 100 may only be able to see one of the two hooks 108 while operating the remote 112. Accordingly, the operator is not able to easily verify that both hooks 108 are properly secured to the object 110 to be lifted without walking around the object 110 and inspecting both hooks 108.
If only one hook 108 of the overhead crane is secured to the object 110 prior to lifting the object 110, the object 110 may be improperly lifted and may tip over, as shown in FIG. 2A. In addition, if one or more of the hooks 108 are not properly secured to the object 110 prior to lifting the object 110, as shown in FIG. 2B, the object 110 may be unstable and may fall while being moved.